Many hand tools are provided with handles oriented in the general configuration of a pistol grip inclined rearwardly to accommodate a comfortable forward facing attitude of the operational end of the tool. Examples are production hand tools such as power driven screwdrivers, wrenches, hammers, hand drills and as particularly illustrated in the present disclosure, rivet gun hand tools.
While the handles are normally oriented in the most comfortable position to accommodate the intended use, ergometric considerations have long revealed inherent muscle fatigue from operation of hand tools with fixed handle orientation, particularly in the case of production tools where the same operation is repeated over prolonged periods of time. Such considerations have established a long felt need for a simple, economic and preferably versatile means for adjusting the angular relationship between the handle and the main body of the tool in order to accommodate occassional change in orientation to relieve hand muscles involved, as well as to optimize handle position for specific, particularly repetitive operations.